Nature

Paropi hitavaan Bandhuhu
Bandhuhu Api Ahitaha Paraha |

Ahito Dehajo vyadihi
Hitamaaranyam Aushadham ||

Though an enemy, if he wishes good he is as good as a relative.
Though a relative if he wishes bad he is as good as an enemy.
Though it’s born and then resides in the body the disease is harmful.
Though its there in the forest, the medicinal plants save lives.

The gist is that it does not matter whether the entity is inside or outside. But its nature matters the most.